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Magnetic composite SERS substrate with core-shell-satellite three dimensional structures and preparation method thereof

A three-dimensional structure, magnetic composite microsphere technology, applied in the direction of inorganic material magnetism, nanotechnology for materials and surface science, Raman scattering, etc., can solve the problems of weak magnetic responsiveness, poor dispersion, poor SERS performance, etc. Achieve the effect of strong sensitivity, low cost and huge application potential

Inactive Publication Date: 2017-01-11
ACADEMY OF MILITARY MEDICAL SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the poor dispersion of existing magnetic SERS substrates, weak magnetic response, and poor SERS performance, and to provide a core-shell-satellite three-dimensional core-shell-satellite with simple fabrication, high dispersion, high magnetic response, and multiple hot spots. Fabrication method of structured magnetic composite SERS substrate

Method used

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  • Magnetic composite SERS substrate with core-shell-satellite three dimensional structures and preparation method thereof
  • Magnetic composite SERS substrate with core-shell-satellite three dimensional structures and preparation method thereof
  • Magnetic composite SERS substrate with core-shell-satellite three dimensional structures and preparation method thereof

Examples

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Effect test

Embodiment 1

[0044] Preparation of a core-shell-satellite three-dimensional structure magnetic surface Raman-enhanced microspheres

[0045] figure 1 A schematic diagram of the preparation process of the core-shell-satellite three-dimensional magnetic surface Raman-enhanced microspheres is given. Its specific preparation method is divided into the following six steps: the first step, using solvothermal synthesis method to synthesize 400nm Fe 3 o 4 Microspheres. Dissolve 2.7 g of ferric chloride hexahydrate in 80 ml of ethylene glycol, and stir magnetically for 30 minutes. Next, 5.4 g of sodium acetate and 2 g of polyethylene glycol 6000 were added to the solution and stirred until the reactants were completely dissolved, then the mixture was transferred to an autoclave (100 ml capacity) with a polytetrafluoroethylene liner and heated to 200 °C for 10 hours. The product was collected with a magnet, washed three times with deionized water and ethanol respectively, and finally the product...

Embodiment 2

[0055] SERS characterization to detect whether the gap formed by polymer PEI is a loose and porous structure capable of accommodating small molecules:

[0056] Synthesized Fe with PEI self-loading layer thicknesses of 1.5nm, 8nm, 18nm 3 o 4 @Ag-PEI microspheres with unmodified Fe 3 o 4 @Ag for contrast. PATP was selected as the Raman molecule. PATP is a commonly used sulfhydryl Raman marker, and it will produce significant chemically enhanced Raman characteristic peaks when combined with gold or silver. Add the four synthetic particles to 1ml with a concentration of 10 -6 Mix and shake in the PATP solution of M for 30 minutes. After magnetic separation, disperse the particle concentrate on a clean silicon wafer, and perform Raman detection after drying.

[0057] Figure 5 It is the experimental result of Example 2. exist Figure 5 The middle abscissa is the Raman shift. Figure 5 The middle curves a, b, c and d represent the PEI self-loading layer thickness of 1.5nm,...

Embodiment 3

[0059] Improve the SERS activity of silver-shell magnetic beads by modifying the surface with satellite-structured gold nanoparticles:

[0060] The SERS activity of the core-shell-satellite three-dimensional structure magnetic SERS substrate modified with 50nm and 25nm gold nanoparticles on the surface was compared with that of unmodified silver-shell magnetic beads. Figure 6 It is the experimental result of embodiment 3. exist Figure 6 Among them, curves b and c respectively represent 25nm gold particles and 50nm gold particles modified core-shell-satellite three-dimensional structure SERS microspheres to detect PATP (10 -11 The characteristic peak of M), curve a represents that common silver-shell magnetic beads detect PATP (10 -9 M) characteristic peaks. This result shows that the detection sensitivity of 25nm gold nanoparticles modified core-shell-satellite three-dimensional structure magnetic SERS microspheres for detecting PATP is 3 orders of magnitude higher than t...

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Abstract

The invention discloses a preparation method of a magnetic composite SERS substrate with core-shell-satellite three dimensional structures. The substrate comprises magnetic composite microspheres which employ silver-shelled magnetic bead (Fe3O4@Ag) microspheres as the cores, cation polymer polyethylenimine (PEI) shell layers as particle inner intervals, and gold nanoparticles (AuNPs) as satellite particles. The preparation method comprises the following steps: the 400nm Fe3O4 microspheres are modified with PEI, 3nm colloidal gold is adsorbed, the microspheres are used as seeds, and Fe3O4@Ag microspheres whose silver shells are continuous are reduced as cores; self-assembly time of PEI is controlled, and PEI forms 1.5nm interval layers (Fe3O4@Ag-PEI) on the surfaces of Fe3O4@Ag microspheres; finally 50nm AuNPs are adsorbed on the surface of Fe3O4@Ag-PEI, and the magnetic composite SERS substrate (Fe3O4@Ag-PEI-Au) with the core-shell-satellite three dimensional structures is formed. The invention also discloses the magnetic composite SERS substrate with the core-shell-satellite three dimensional structures, which is prepared by the method; the substrate has the advantages of good magnetic induction, good dispersibility, stable structure, and multiple hot spots; the substrate can be directly applied to SERS detection of various micromolecule pollutants, pesticide residues, illegal additives of foodstuff, and the like.

Description

technical field [0001] The invention relates to the fields of nanomaterials and biochemical spectrum analysis and detection, in particular to a magnetic composite SERS substrate with a core-shell-satellite three-dimensional structure and a preparation method thereof. Background technique [0002] In 1974, Fleischmann et al. found that using a rough silver electrode as a carrier of pyridine molecules, the Raman signal of the latter was abnormally and greatly enhanced (about 10 6 times). This Raman-enhancing effect associated with rough noble metal (gold, silver, and copper) surfaces is called surface-enhanced Raman scattering (Surface Enhanced Raman Scattering, SERS). SERS is a powerful fingerprint vibration spectrum, which has the advantages of high sensitivity, high selectivity and fast non-destructive detection, and is widely used in biochemical detection, sensors, analytical chemistry and environmental monitoring and other fields. However, all these applications are lim...

Claims

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Application Information

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IPC IPC(8): G01N21/65H01F1/10B82Y30/00B82Y40/00
Inventor 王升启肖瑞汪崇文蒋娜荣振庞元凤王俊峰
Owner ACADEMY OF MILITARY MEDICAL SCI
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